Is Chemical Recycling Greenwashing?
Conor McGlone | November 7, 2022 | E&T Magazine
The US has a serious plastic problem. Over the summer it emerged that the recycling rate of the ubiquitous material had sunk to less than 6 per cent. For context, the European Union together with Norway, Switzerland and the UK recycled on average 37 per cent of the plastic waste they generated in 2020.
The US generates more plastic waste than any other country in the world, according to the Organisation for Economic Co-operation and Development (OECD). In 2019, Americans generated 220.5kg of plastic waste per person, whereas Europeans generated an average of 121.6kg. Plastic production is expected to increase dramatically, with the amount of plastic waste produced globally on track to almost triple by 2060. Around half of this will end up in landfill and less than a fifth will be recycled, according to the OECD.
Given this trajectory, Dr Neil Tangri, science and policy director at the Global Alliance for Incinerator Alternatives (GAIA), says that, like others, he was encouraged when chemical recycling began to emerge on the scene around three years ago.
Chemical recycling is a broad term used to describe a range of technologies which the petrochemical sector claims can recycle plastic that is traditionally difficult to deal with mechanically. In the US, petrochemical companies are beginning to invest seriously in these technologies. The body that represents petrochemical companies in the US, the American Chemistry Council (ACC), says the country is “truly on the cusp of a massive scale up” of chemical recycling. Only in October, the US’s largest oil and gas firm, ExxonMobil, announced it was launching 13 chemical recycling facilities that would recycle 454,000 tonnes of plastic waste by 2026.
Yet if this sounds too good to be true, many scientists and green groups in the US and Europe have told E&T they think it is. “When I heard there are new technologies able to recycle plastic in a different way, I thought ‘great, finally’. And then we started digging into it. After three years of research, we have come back very disappointed,” says Tangri.
Chemical recycling aims to turn plastic waste back into its molecular building blocks, in contrast to mechanical recycling, which does not alter the chemical structure of the plastic. By far the most prevalent type of chemical recycling, pyrolysis is a process in which plastics are broken down into a range of basic hydrocarbons by heating in the absence of oxygen. The primary product is pyrolysis oil, which can be refined into fuels or further processed to create chemicals or plastic.
Gasification uses high temperatures with low volumes of air or steam to degrade plastic. The primary product is a gas called ‘synthesis gas’, which can be processed into fuels or chemicals. Other forms of chemical recycling include solvent-based processes, which dissolve plastics and separate polymers from other components. Chemical depolymerisation uses thermal and chemical reactions to break the plastic polymer chain into individual monomers
Joshua Baca, vice president of plastics at the ACC, says chemical recycling is critical because plastics, “whether recycled or virgin, are essential to modern life, and now we are making changes to how we manufacture plastics, using alternative and recycled feedstock, to advance a circular economy with the lowest carbon footprint”.
The petrochemical sector has promoted chemical recycling under many different guises including chemical conversion, molecular conversion and feedstock recycling. Today its preferred choice is advanced recycling.
Janek Vähk, climate, energy and air pollution programme coordinator at Zero Waste Europe (ZWE), says the name change came about because the word chemical “conveys toxicity”.
Advanced recycling is also preferred because this implies all types of plastic can be completely recycled, he adds. “In the beginning [petrochemical companies] claimed it was 100 per cent that could be recycled. They said it’s like taking a cake back to its original components of flour, sugar, butter and eggs.
“But we realised you cannot ever get it back to its original components – you lose a lot of material in the process. It was a marketing exercise,” says Vähk.
Both mechanical recycling and depolymerisation struggle to process much of the plastic waste we generate, such as sweet wrappers, crisp packets, single-use cups and cotton swabs. These materials are made of multiple plastics like polyethylene and polypropylene, which are notoriously difficult to separate. They also have strong carbon-carbon bonds that resist depolymerisation. Pyrolysis is viewed as the only current viable way of recovering the raw materials from this waste stream.
However, notes Vähk, more than 50 per cent of the original carbon in the plastics is lost during the pyrolysis process, while the resulting pyrolysis oil requires further energy-intensive purification before it can be used as a feedstock for polymer production at petrochemical plants known as steam crackers. This has major implications.
A plethora of recent reports in the US have raised concerns about the environmental impact of chemical recycling. Earlier this year, US NGO the Natural Resources Defense Council (NRDC) conducted in-depth research on eight chemical recycling facilities in the country. It concluded that the facilities are “generating hazardous waste and exacerbating environmental injustices under the false guise of recycling”. It said most facilities are not producing or planning to produce new plastic but are performing “a kind of plastic incineration – turning plastic into dirty fuel using energy-intensive processes”.
